Abstract

Concrete is the most widely used construction material around the world because of its high strength and low cost as compared to alternatives. However, concrete structures tend to deteriorate over time due to various factors which include sulphate attack, severe weather conditions etc. and that is why concrete structures require repairing works after a certain span of time. The problem that arises is that the bonding between old and fresh concrete is poor and most of the times structures do fail at the interface. Commonly, mechanical methods are used which normally involves roughening of surface of old concrete before the addition of fresh concrete but in modern market, number of chemicals are available in market that can contribute to the bonding strength at the interface. This research covers both type of methods for bonding which includes roughening of surface as mechanical method and addition of locally available bonding agent in different compositions as chemical method. Also concrete that was added on top of old surface was of different types to check whether that would have any effect on the bonding at the interface. It was found out that the bonding agent did improve the bond strength at the interface by 20 percent although it did not have any effect on the compressive strength of concrete.